| 616 | coeffs[3] = 1.f - coeffs[0] - coeffs[1] - coeffs[2]; |
| 617 | } |
| 618 | static GI_FORCEINLINE void interpolate_lanczos4(float x, float* coeffs) { |
| 619 | static const double s45 = 0.70710678118654752440084436210485; |
| 620 | static const double cs[][2] = {{1, 0}, {-s45, -s45}, {0, 1}, {s45, -s45}, |
| 621 | {-1, 0}, {s45, s45}, {0, -1}, {-s45, s45}}; |
| 622 | |
| 623 | if (x < FLT_EPSILON) { |
| 624 | for (int i = 0; i < 8; i++) |
| 625 | coeffs[i] = 0; |
| 626 | coeffs[3] = 1; |
| 627 | return; |
| 628 | } |
| 629 | |
| 630 | float sum = 0; |
| 631 | double y0 = -(x + 3) * MEGCV_PI * 0.25, s0 = sin(y0), c0 = cos(y0); |
| 632 | for (int i = 0; i < 8; i++) { |
| 633 | double y = -(x + 3 - i) * MEGCV_PI * 0.25; |
| 634 | coeffs[i] = (float)((cs[i][0] * s0 + cs[i][1] * c0) / (y * y)); |
| 635 | sum += coeffs[i]; |
| 636 | } |
| 637 | |
| 638 | sum = 1.f / sum; |
| 639 | for (int i = 0; i < 8; i++) |
| 640 | coeffs[i] *= sum; |
| 641 | } |
| 642 | |
| 643 | template <typename T, typename WT, typename AT> |
| 644 | struct HResizeLanczos4 { |
no test coverage detected